Method of drying milk.



0. HIGOLAI. HETHOf) or 111mm mm. APPLIOATIIIF. FILED JAR. 31, 1912.

' 11,068,581 Patented June 3, 1913.

i mmmxmwwmmmwm m and maintaining a certain temperature for fication. r

UNITED STATES PATENT OFFICE.

OSCAR moorhu", for I ERSEN, GERMANY.

"' METHOD or nmzma MILK.

Specification of Letters Patent 1 Patn tefl J 11113 3;1913

- Application filed 'J'anuary 1, -1a1aa-se1fi1'wo. 874C482 To all whom it may concern Be itknown that I, OSCAR NICOLAI, a citizen ofthe Empire of Germany, residing at Viersen," in the Empire of Germany, have invented anew and useful Method' of Dry-' ing Milk, of which the following is a specisents a vertical longitudinal section through a building and shows in elevation. I

For attaining the object indicated above it is essential that the milk be not altered by the drying process as igegards its physical and chemical properties. This canhe effectthe' several apparatus ed only in' themanner, that during the evaporation and drying of the milk certain dilierent temperatures be maintained and all-- lowed to severally act upon the milk only for certain periods. At temperatures be tween 40 and centigrade no disadvantageous alteratidn ot' the constituents of the milk-takes .place, it' is "true, however theproduct obtained-by drying at this temperature will after a short-timeshow a disagreeable taste and smell. Such a product may be perfectly treetrom germs in spite of its altered taste, however, it has undergone special alterations which have 'not been cleared up yet. 4

.irccording to my invention a productsta ble tor a long time can be obtained by dividing the drying operationintofour stages each stage during a certain period,- the various stages closely following one after the other and forming a single coherent process. In the first stage of the process temperature of from 60 to 80 Centigrade is maintained for about from half an hour to one. hour, so as to brlng the "Inllk into such a 'state,-that itsspeci-fic weight at the said;

in a quitegthindl'ajyer *for about front-{10 to 20 seconds to theaction of a temperature of about from 90 to100 centigrade. In

=the third, stage the milk skin: as thin as paper is first cooled andthen exposed for about-half an hour. to theac'tion of-a temperature of from 60t0 80 Centigrade. In the fourth stage the milk heated up to from '60 to 80 ce'ntigrade is rapidly cooled.

Fzrst stage.',The temperaturev and the duratioii mentioned above prevent the formation of injurious bacteria in the milk during the. evaporation, whereas such bacteria mightbe easily jormcd at temperatures of from 40f to50 centigrade, for example by drying in vacuo. The said temperature and dtll'iltlOIl also prevent disadthe milk.

vantageous alterations of the constituents of For carrying into effect; the first stage of the.- process an evaporating apparatus of any approved construction is employed. for example one marked 9' in the drawing. which will be referred to later on.

- Second stage-'Iemperaturcs of from '90 to 1.00 Centigrade would prove injuriuus'to the product, if they were permitted to act -upon the milk for a longer time.- For this reason the duration of the OXD(. lll()l1 of the 10 to QO-secohds, as mentioned above. During this short period the temperature should .also never exceed 100 centigrade, since otherwise detrimental alterationsof the milk constituents would take place.

For carrylng into elfect the second stage of the'process a drying apparatus of any :11)-

n ilk to these temperati'ires limited to from proved construction, for example acylinder drying machine, is employed. such .as is marked (Sin the drawing and to be referred .thirdstages, yet the latteris niade to closely followlhe former m The purpose-of the third I period is to far'emove the superfluous moisture from the milk excepting the .walt

of crystallization of the milk sugar and to :marked 12 in the drawing. and

form ay'product perfectl'y free from germs. For carrying into effect the third stage a suitable drying apparatus of any approved construction is employed, for example one ferred to later on.

. Fourth s'tag'e.The dried milk possessing.

.a temperature .ofabdut from 60 to. 80

centigrade requires .to be cooled to ordinary temperature and also to be'reduced in shape, in other words to be turned into an article of commerce. i

For carrymg into effect the fourth stage of the process a cooling apparatus and a reducing or breaking or grinding orpulverizing-machine of any approved construction are employed. Such machines will be here'- ina fter referred to.

,In the drawing 1; denotes a reservoir of any known construction, inwhich the milk;

to be dried-is stored up. p

The evap ating apparatus 2 may c'omprise-a semicircular,trough below, a semicircular hood -above, a horizontal central hollow shaft mounted in brackets '3 .to turn and carrying'a number of parallel hollow" or the like partly dip in the milk and con-' stantly rotate, so that by the contactwith the hot walls of the heating bodies the milk is graduallyevaporated and thickened to a certain degree, so as to comply with the conditions mentioned above,

A ventilator or exhauster 4' shown tobe connected with the hood of the evaporating apparatus 2 by meansof a tube 5 serves for discharging the steam developed from the milk into the-atmosphere or somewhere else. By means of the ventilator orexhauster at a current of hot or cold air can beset up.

The cylinder drying machine (3 may comprise-two superposed hollow cylinders of different. diameter, a trough beneath the lower small cylinder, a hood in'closing about:

two thirds of the upper large cylinder and connected with the ventilator or exhauster 4 by means of a tube 7 and means for supplying steam or other heating medium to the two cylinders. The troughs of both the evaporating apparatus '2 and the-cylinder drying machine 6 may, be connected together by means of tubes and stop valves (not'shown) or the like, so that-from" time to time the thickened milk can be discharged from the trough of. the evaporating apparatus 2 to that of the drying imachine ti. The lower small cylinder in'the latter isvertically adjustable and mostly dips in the thickened milk in the trough, so that during its; rotationit is adapted to applya quite thin layer of milk to the periphery of the upper large cylinder. This layer of milk isfurther dried by means of thesteam or other heating medium. The .ventilator or exhauster 4 produces a. current of hot or coldair for carrying oil? the steam developed .from the layer. of milk on the largecylinder.

Thermometers and other instruments are.

provided for controlling the second stageof the method; Some known devices, such as a scraper-or the like may be employed for scraping the mostly dried'milk, thatis a :thin milk skin, oi? the large cylinderfand an endless' apn'on '8-of any approved construct-ion may 'be employed for receiving the scraped off mostly dried milk and delivering itup to some known conveyer '9, that is an endless'screw 'working inan open channel.

Of course other apparatus maybe employed for conveying the mostly dried milk. An

elevator 10 is-sho'wn to bedi'sposed for receiving, themjostly dried milk fromthe con.-

yeyer 9, elevating and discharging the milk through a chute 11 to the drying apparatus 12." Obviouslythe path from tlie cyl-inder drying machine '6 over the endless apron 8 and through the conveyor 9, the elevator 10 aid the chute'll to thedrying apparatus 12 means a pause between the second and third stages, as, mentioned above. i

The drying apparatus 12 may comprise a long rectangular casing, one or several round or'a'ngular drums mounted therein to turn and means for sending a current of hot air through the drums, also means for regulating the temperature in the apparatus. The mostly dried milk enters one drum at one end and is kept moving or rolling. duringthe rotation of the drum, while being completely dried up by the current of hot air. Thermometers and other instruments are provided for watching the operation of the drying apparatus 12. The completely dried hot, milk leaving the one drum or several drums is discharged into a conveyor 13 .wdrking in a channel cooled from without by means of cold water, so that the dried milk is thereby cooled. The cooled dried milk is discharged from the conveyor 13 through a tube or' chute 1 L into a reducing -or sifting machine 15, which may comprise a' hopper, a! brushing roller and a sieve. During the rotation of this roller the milk may be reduced or brokenand driven through the holes of the sieve. The product so obtained can be packed for sale. Of course any other machine may be employed for grinding or otherwise finishing the drie milk, as may be preferred.

' several apparatus by means of endless belts (not shown).

I claim: r 1. Method of treating milk which consists in heating the milk so as t-othicken the same, spreading the thickened milk in a dephlegmated skin.

to one hour to the thin stratum, heating said stratum to a higher degree for a short period to form a skin, cooling the skin, reheating the same to expel the moisture, and. cooling the 2. The method 'of drying milk consisting in exposing the milk for from half an hour action of a temperature of about. 65 to 85 centigrade so as to thicken the milk up to about 6 to 9 Baun immediately afterward exposing the nnlk in a thin layer forfaliew seconds to the action of a temperature of about 90 to 100 centigrade, so as to turn the milk into a Wet milk skin as thin as paper, thereupon cooling the mostly dried milk, exposing it for half an hour to the action of a temperature of about 65? to 85 centigrade so as to free it from water excepting the Water of crystallization of the milk sugar, and. cooling the completely dried milk. T OSCAR NICOLAI." [Ls] Witnesses: i I

HELEN NUFER, v WILHELM SoNNooK. 

